diff --git a/drivers/s390/cio/ccwgroup.c b/drivers/s390/cio/ccwgroup.c
index 5535312..838752e 100644
--- a/drivers/s390/cio/ccwgroup.c
+++ b/drivers/s390/cio/ccwgroup.c
@@ -326,8 +326,7 @@ int ccwgroup_create_dev(struct device *parent, struct ccwgroup_driver *gdrv,
 	if (num_devices < 1)
 		return -EINVAL;
 
-	gdev = kzalloc(sizeof(*gdev) + num_devices * sizeof(gdev->cdev[0]),
-		       GFP_KERNEL);
+	gdev = kzalloc(struct_size(gdev, cdev, num_devices), GFP_KERNEL);
 	if (!gdev)
 		return -ENOMEM;